The ship pulled away from Nagasaki harbor on the morning of February 20, 1582, and four boys stood at the rail watching Japan disappear into the winter haze. They were thirteen and fourteen years old. They had been chosen because their families were connected to the Christian daimyo of Kyushu — lords who, at that moment, genuinely believed Japan was on the verge of becoming a Catholic nation. The boys carried letters, hopes, and a mission designed by an Italian Jesuit named Alessandro Valignano, who understood something the Japanese lords did not yet: that showing the Pope a Japanese face would be worth more than any amount of theological argument.

The four boys were Mancio Ito, Miguel Chijiwa, Juliao Nakaura, and Martinho Hara. Their journey would last eight and a half years. They traveled via Macau and Goa, arriving in Lisbon on August 11, 1584 — two and a half years after departure. From Lisbon they went to Madrid, where they met King Philip II of Spain, then onward to Rome, where they met two popes in succession. Gregory XIII (who had helped sponsor the mission) died before the formal audience could be completed; Sixtus V received them in its place, was reportedly moved to tears by the encounter, and knighted all four into the Order of the Golden Spur — an ancient European honor that had been conferred on the composer Palestrina and would later be given to the young Mozart. These four Japanese teenagers joined an honor society centuries older than their own country's contact with Europe.

They also visited Francesco I de' Medici, Grand Duke of Tuscany, and were celebrated across the continent as proof that Christianity had truly reached the ends of the known world. The Jesuits used them brilliantly: their presence was living evidence that the mission in Japan was real.

Then they went home.

They returned to Nagasaki in July 1590. In the eight and a half years they had been gone, the political landscape of Japan had transformed entirely. Toyotomi Hideyoshi (豊臣秀吉, Toyotomi Hideyoshi) had issued his edicts expelling Christian missionaries in 1587. The Christian daimyo who had sent the boys were dead, or older, or navigating a world where their faith had become a liability. Otomo Sorin (大友宗麟, Otomo Sorin), the most powerful of their patrons, had died in June 1587 — three years before they returned, still a Christian, never knowing if his ambassadors had made it back.

Hideyoshi summoned the returned envoys to meet him in 1591. The encounter was strange: the man who had banned the religion brought back by these boys was fascinated by everything else they carried with them. He demanded performances of the Western music they had learned in Europe. He asked for encores. The persecutor of their faith could not get enough of the sounds they had brought from Rome.

The four boys were eventually ordained as Jesuit priests. And then their fates diverged as widely as the religion they served was scattered.

Mancio Ito died of illness in 1612, the most peaceful end. Martinho Hara was eventually banished to Macau and died there in 1629, far from the country he had once represented to the world. Juliao Nakaura stayed in Japan and worked as an underground priest through the years of persecution; he was captured and died a martyr by torture in 1633, and was beatified by Pope Benedict XVI in 2008 — more than four centuries after he had knelt before Sixtus V.

Miguel Chijiwa's fate is the most haunting. He left the Jesuits around 1601 and is generally recorded as having renounced Christianity. But in 2017, archaeologists excavated his grave — and found rosary beads buried with him. Whether he had maintained a secret faith to the end, or whether someone who loved him had placed them there, no one can say.

The 天正遣欧少年使節 (Tensho Keno Shonen Shisetsu) — the Tensho Youth Mission to Europe — was the last open diplomatic contact between Japan and the Western world for over two centuries. The sakoku (鎖国, sakoku) isolation edicts of the 1630s sealed Japan from Western contact until Commodore Perry's ships arrived in 1853. The four boys who sailed from Nagasaki in 1582 had been ambassadors of a possible future — a Japan embedded in the Catholic world, in diplomatic conversation with Europe, part of a global civilization. They returned to find that future had been locked away.

They had left as boys and returned as men, carrying a world that no longer fit the country they had come home to.